Full Idea
Two sentences are synonymous if they have the same meaning, suggesting that they must both be meaningful. On the face of it the English 'two is green' and French 'deux est vert' are synonymous, suggesting meaningful category mistakes.
Gist of Idea
If a category mistake is synonymous across two languages, that implies it is meaningful
Source
Ofra Magidor (Category Mistakes [2013], 3.3)
Book Reference
Magidor,Ofra: 'Category Mistakes' [OUP 2013], p.58
A Reaction
I'm fairly convinced already that most category mistakes are meaningful, and this seems to confirm the view. Some mistakes could be so extreme that no auditor could compute their meaning, especially if you concatenated lots of them.